THESIS
2021
1 online resource (vii, 87 pages) : illustrations (chiefly color)
Abstract
A Bayesian network is a probabilistic graphical model that aims to model conditional dependence
(causation) among variables. In most cases, the true underlying structure of a set of variables is
unknown. The number of possible structures grows explosively when we have more variables in
the networks. Recovering the structure from a given data set is challenging. Many existing algorithms
can learn structures from data automatically, but those algorithms may not be able to handle
networks with hundreds or thousands of nodes. The focus is a score-based approach. However,
sampling the partial order from a graph using MCMC methods requires intensive computational
time, and the sampling scheme is biased. We develop a new MCMC sampling scheme for
structural learning. The proposed sampling schem...[
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A Bayesian network is a probabilistic graphical model that aims to model conditional dependence
(causation) among variables. In most cases, the true underlying structure of a set of variables is
unknown. The number of possible structures grows explosively when we have more variables in
the networks. Recovering the structure from a given data set is challenging. Many existing algorithms
can learn structures from data automatically, but those algorithms may not be able to handle
networks with hundreds or thousands of nodes. The focus is a score-based approach. However,
sampling the partial order from a graph using MCMC methods requires intensive computational
time, and the sampling scheme is biased. We develop a new MCMC sampling scheme for
structural learning. The proposed sampling scheme can potentially handle the problem of biasedness
in existing methods. We demonstrate in simulations that our proposed method is more efficient
to allow the graph samples to enter high score areas. We also illustrate our sampling scheme
in a social science research study.
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